Ecosystem changes

Florida's coral reefs, a vital marine ecosystem, have been under severe threat due to extreme ocean temperatures this summer. The coral reefs, besides being biodiversity hotspots, also serve as a protective barrier against coastal erosion and are a significant source of revenue through tourism.

Efforts to protect and restore these reefs have been ongoing for decades. Coral restoration, which involves planting coral fragments, has been a primary method employed by scientists.

Seaweed in the Atlantic

These sprawling masses of seaweed, often stretching for miles, have been observed in the Atlantic over the past few years. While such occurrences are not entirely new, their increasing frequency and size have raised concerns about their potential environmental impacts.

A recent in-depth exploration by BBC Future sheds light on the phenomenon, unraveling the complex factors behind the enigmatic seaweed blooms.

Ocean deoxygenation has detrimental repercussions. Fish, crabs and other significant species of marine life that are unable to flee these low oxygen zones may perish as a result. People who depend on them for food and employment may be subsequently impacted by their absence as many of these species are economically significant.

Additionally, there is a negative feedback loop at play: as ocean oxygen levels decline, so does its capacity to absorb carbon dioxide. This may cause global warming to accelerate even further.

First spotted in the Atlantic Ocean off Florida in the 1980s, they later spread across the Caribbean, reshuffling coral reefs and other ecosystems by feasting on fish unfamiliar with the voracious predator.

While ocean currents that flow north—such as the South Equatorial Current—and the freshwater plume created by the Amazon River hampered the spread of the invasive species, scientists predicted it was just a matter of time before it moved into Brazilian waters.

Like other fish, minnows can adjust their body temperatures to match that of their surroundings.

Research into the effects of climate change on fish generally focus on their heat tolerance at an increase of two or three degrees Celsius above the current average temperatures.

However, a recent University of Illinois study wanted to find out how fathead minnows handled short-term temperature spikes—those amounting to as much as 5 to 10 degrees Celsius above average.

Corals are able to respond to changes in their environment through acclimation (the physiological process of becoming accustomed to a new condition) and adaptation and researchers believe natural populations may already be adapting to increasing sea surface temperatures.

Rather than causing a collapse of biodiversity, the dual stressors of ocean warming and acidification could instead lead to significant changes in the relative abundance of species, resulting in a shuffling of coral reef community structure, according to a new study by researchers from University of Hawai'i.

Sprawling coral reefs are complex ecosystems that are teeming with life and most of this biodiversity consists of tiny organisms living deep within the three-dimensional reef matrix.

Atolls are often only around two meters (6.6 feet) above sea level, but sea levels could rise by more than that by the end of this century, according to prevailing climate models. Four atoll nations -- the Marshall Islands, Tuvalu, Kiribati, and the Maldives, which are together home to more than half a million people -- were the most vulnerable on the planet to climate change but under threat was also those in the Caroline Islands, Cook Islands, Gilbert Islands, Line Islands, Society Islands, Spratly Islands, Seychelles, and Northwestern Hawaiian Islands.

Lionfish, which have spines that contain venom, are a well-known problem in Atlantic coral reefs. These invaders from the tropical parts of the Pacific and Indian oceans have no natural predators in the Atlantic Ocean. They are eradicating many fish populations in the shallow reefs that they have overtaken. Recently, the overwhelming problem has proven worse than originally thought.